---
title: Core Web Vitals
description: "LCP, INP, and CLS are Google's three page-experience metrics. Understand the thresholds and fix them without guessing."
canonical: https://penasihathosting.com/en/hosting-wiki/core-web-vitals
type: wiki
locale: en
updated: 2026-10-29
author: Willya Randika
---

# Core Web Vitals

## Overview

- **Summary:** LCP, INP, and CLS are Google's three page-experience metrics. Understand the thresholds and fix them without guessing.
- **Author:** Willya Randika ([profile](/penulis/willya-randika))

## Article

**Core Web Vitals** are the three metrics Google uses to measure page experience: **LCP** (how quickly the main content loads), **INP** (how responsive the page is to interaction), and **CLS** (visual stability). Since 2024, INP has replaced FID.

## The thresholds

| Metric | Meaning | Good | Needs improvement | Poor |
| --- | --- | --- | --- | --- |
| LCP | Time until the largest element is visible | ≤ 2.5 s | 2.5–4 s | > 4 s |
| INP | Response to clicks and typing | ≤ 200 ms | 200–500 ms | > 500 ms |
| CLS | Unexpected layout shifts | ≤ 0.1 | 0.1–0.25 | > 0.25 |

These numbers come from field data (CrUX), not only the lab. PageSpeed Insights can differ from real user experience because of device, network, and location.

## Common causes

- **Slow LCP:** oversized hero images, high TTFB, render-blocking CSS/JS, slow fonts.
- **Poor INP:** heavy JavaScript, long event handlers, third-party scripts, slow hydration.
- **High CLS:** images without dimensions, injected ads/embeds, font swaps that move text.

## Fix without guessing

Measure first in **PageSpeed Insights** and **Search Console → Core Web Vitals**. Fix the largest cause, then measure again after cache and CDN behavior is consistent. For LCP, check [TTFB](/en/hosting-wiki/ttfb) and [web cache](/en/hosting-wiki/web-cache). For assets, compression and a [CDN](/en/hosting-wiki/cdn) often help.

## What to watch for

- **Field data wins.** Good lab data does not guarantee good field data.
- **Mobile is stricter.** Test on realistic devices and networks.
- **Third-party scripts are expensive.** Every analytics or chat tag adds JavaScript cost.
- **Do not chase a score of 100.** The thresholds matter, not a cosmetic number.

## FAQ

<Accordion>
  <AccordionItem title="Are Core Web Vitals a ranking factor?">
    Google uses page experience as one signal, but relevance and content quality remain far more important.
  </AccordionItem>
  <AccordionItem title="Why is lab data good but field data poor?">
    Lab tests usually use fast devices and networks. Field data reflects real visitors with different devices, locations, and connections.
  </AccordionItem>
  <AccordionItem title="Which metric should I fix first?">
    Start with LCP if the page feels slow, then INP if interactions lag. CLS is usually the cheapest to fix by setting image dimensions.
  </AccordionItem>
</Accordion>